Sciencemadness Discussion Board

Citric acid + acetic acid=

apathy - 17-3-2014 at 20:27

I drink apple cider vinegar to help with stomach problems, but the taste is almost unbearable. If I mix it with orange juice in a 1:4 ratio it all most completely covers up the taste.

I have heard that acids sometimes counteract each other and I wonder if that is why it covers the taste up so well

I could just try it for awhile and see if the problems return, but I don't want to test the theory if I don't have to. Thanks in advance.

numos - 17-3-2014 at 20:57

I'm no wine taster so I don't know about covering up the taste, but I doubt there is a reaction between those two acids.

thesmug - 17-3-2014 at 21:59

numos is right, chemically nothing would happen as they are both weak organic acids. I know that NaHCO3 can act as a base and or an acid depending on circumstance, but I've never heard of an acid neutralizing an acid. As for the taste, I think it has very little to do with the citric acid and more simply because orange juice has such a strong (for lack of a better term) flavor.

Pyrovus - 18-3-2014 at 07:36

Theoretically you could make the acetic ester of citric acid (it does have that hydroxyl group, after all), but generally esterification reactions need strongly acidic conditions. It's much more likely that all the various flavour molecules present in orange juice are simply drowning out the vinegar flavour.

Antiswat - 18-3-2014 at 10:25

slightly offtopic: vinegar and NaCl is very effective on cleaning coins, by what i SUPPOSE, vinegar is not stronger acid than HCl, so why would it form HCl with NaCl?
HCl very effectively removes copper oxides

HgDinis25 - 18-3-2014 at 10:30

Quote: Originally posted by Antiswat  
slightly offtopic: vinegar and NaCl is very effective on cleaning coins, by what i SUPPOSE, vinegar is not stronger acid than HCl, so why would it form HCl with NaCl?
HCl very effectively removes copper oxides


Are you sure HCl is formed? Vinegar, by itself, can easily with copper oxide (assuming copper oxide is the "dirt" on coins). The Sodium Chloride aditions is, probably, to add an abrasive. Sodium Chloride also wokrs well as an abrasive when cleaning dirty glassware.

elementcollector1 - 18-3-2014 at 10:44

The understood reaction is that the chloride ions and hydrogen ions form an equilibrium of HCl, which attacks the copper oxide. Vinegar alone is too weak to do anything, and it would take movement and abrasion of the surface of the pennies by the salt (which can't happen in a dissolved solution) to clean them physically.

[Edited on 3-18-2014 by elementcollector1]

HgDinis25 - 18-3-2014 at 11:05

Quote: Originally posted by elementcollector1  
The understood reaction is that the chloride ions and hydrogen ions form an equilibrium of HCl, which attacks the copper oxide. Vinegar alone is too weak to do anything, and it would take movement and abrasion of the surface of the pennies by the salt (which can't happen in a dissolved solution) to clean them physically.

[Edited on 3-18-2014 by elementcollector1]


When refering to the abrasive properties of NaCl I was obviusly talking about it not in solution. My grandmother, for instance, uses lime juice and salt to clean copper (same effect here, only with citric acid). I supposed the effec here was the same. And vinegar has already a good concentration of acetic acid, that would do the job dissolving copper oxide (I've done it myself).
I always thought that the equilibrium constant would be too low to make any decent concentration of HCl, but I'm probably wrong in this.

Zyklon-A - 18-3-2014 at 11:16

http://www.sciencemadness.org/talk/viewthread.php?tid=23728
I doubt any notable reaction occurs.

[Edited on 18-3-2014 by Zyklonb]

Random - 18-3-2014 at 12:52

Solution gets diluted and is masked with orange flavor compounds.

DraconicAcid - 18-3-2014 at 13:31

Quote: Originally posted by elementcollector1  
The understood reaction is that the chloride ions and hydrogen ions form an equilibrium of HCl, which attacks the copper oxide.


No- there are no HCl molecules in any dilute aqueous solution, because HCl is a strong acid. What happens is that the chloride ions can coordinate to the copper ions, which helps the weakly acidic solution dissolve the oxide.

elementcollector1 - 18-3-2014 at 13:54

Ah. Evidently I have to have a few words with my school's chemistry department...

HgDinis25 - 18-3-2014 at 14:10

Quote: Originally posted by elementcollector1  
Ah. Evidently I have to have a few words with my school's chemistry department...


Hahaha, another exemple of school doing it's job: misinformating it's students.
Yesterday, at school, we were told to handle a 0,1M solution of acetic acid and my teacher (who hates me because of all my chemistry knowledge, half of it coming from this forum) started yelling at me for not using the acid in a fume hood. People, c'mon, my vinegar is 10 times more concentrated than that and I temper my salad in my kitchen table...

DraconicAcid - 18-3-2014 at 14:19

Quote: Originally posted by HgDinis25  
Yesterday, at school, we were told to handle a 0,1M solution of acetic acid and my teacher (who hates me because of all my chemistry knowledge, half of it coming from this forum) started yelling at me for not using the acid in a fume hood. People, c'mon, my vinegar is 10 times more concentrated than that and I temper my salad in my kitchen table...


When we do a lab with vinegar at my college, we try to leave it in the fume hood, just so that the students don't complain about the smell of white/red wine/balsamic/apple cider vinegars all mingling together.

And so that I don't start craving french fries quite so much.

elementcollector1 - 18-3-2014 at 14:41

I temper my salad with a coal forge (for maximum nostalgia) and a quenching bucket.
(Blacksmithing jokes!)
Anyway, it's probably not so much misinforming as it being dumbed down, and then presented (misinformedly) to demonstrate a concept, in this case equilibrium.

HgDinis25 - 18-3-2014 at 14:49

@DraconicAcid I smeled the acid (bad lab procudere :D), I smeled a faint scente of it.

Oh, she also said that those (http://www.ycrongkang.com/product.asp?Product_ID=860) aren't plastic pasteur pippetes and that I am absolutly wrong when even calling them pippetes. They must be called eye droppers, acording to her. I lost my temper in that class...

jwpa17 - 18-3-2014 at 20:09

When you mix acetic acid (pKa 4.75) and citric acid (pKa 3.08), the mixture would be less acidic than the stronger of the two, but more acidic than the weaker. Both have equilibria involving protons, so the equilibria are coupled.

The above disregards the concentrations. According to Wikipedia, the pH of white vinegar is about 2.4, that of orange juice is 3.5. So the concentration of citric acid in OJ must be considerably less than that of acetic acid in white vinegar (about 1 M).

So, adding vinegar to OJ, some of the citric acid will protonate the available acetate. But probably the biggest effects are due to dilution and the sugar and flavor in the OJ.

[Edited on 19-3-2014 by jwpa17]

DraconicAcid - 18-3-2014 at 20:20

Quote: Originally posted by jwpa17  
When you mix acetic acid and citric acid, the small amount of citrate present deprotonates some of the acetic acid, since citric is a weaker acid than acetic acid. Both equilibria are happening in the same solution, and share protons in common. In other words, the citric acid slightly reduces the acidity of the vinegar. I'm sure the dilution and the sugar in the OJ also affects the taste.


No- if you mix a weak acid with an even weaker acid, the solution of the weak acid will become less acidic only because of the dilution.

If you have a solution of HX and HY (where HX has a significantly larger Ka than HY), the presence of HX will prevent HY from ionizing very much, but the presence of HY will not affect the ionization of HX.

jwpa17 - 18-3-2014 at 20:27

No, the conjugate base of the weaker acid will deprotonate the acid of the stronger acid. What you describe amounts to two independent equilibria, not possible if they share a species in common.

DraconicAcid - 18-3-2014 at 20:41

Quote: Originally posted by jwpa17  
No, the conjugate base of the weaker acid will deprotonate the acid of the stronger acid. What you describe amounts to two independent equilibria, not possible if they share a species in common.


No, because there will be barely any of the conjugate base of the weaker acid present in solution.

apathy - 22-3-2014 at 07:15

Alright I've been using the oj vinegar cocktail for a few days. Yesterday I decided to test it I drank a cup of the mix and ate a flamethrower grillburger from dairy queen last night and I ate my fries with mayo mixed with daves insanity sauce. Woke up this morning with no problems. I think I have the system beat.

Thanks for the help

Texium - 24-3-2014 at 19:02

Yech, that Dave's Insanity sauce… scary stuff that!